The present invention relates generally to an eddy current proximity system and, in particular, to methods and systems used to facilitate reducing circuit noise in a digital eddy current proximity system.
At least some known eddy current proximity systems may experience signal noise that affects an output from an eddy current transducer coupled to the system. For example, an analog eddy current proximity system may experience relatively consistent noise of approximately ten millivolts (mv) peak-to-peak over a span from approximately ten mils to approximately ninety mils of gap between the transducer and a target. In contrast, within at least one known digital eddy current proximity system, the noise is of relatively low amplitude, for example, approximately seven mv peak-to-peak at ten mils gap, but increases to approximately fifty mv peak-to-peak at ninety mils gap.
Accordingly, at least some known digital eddy current proximity systems use a table lookup and interpolation to determine gap. When using a single frequency, the digital eddy current proximity system uses only the table that corresponds to the specific frequency that is used to excite the transducer, which is also the frequency used to build the table. However, limiting the digital eddy current proximity system to only one frequency and only one look-up table may limit an accuracy of the digital eddy current proximity system.